WAVELENGTH-DEPENDENT PHOTOCHEMISTRY OF ALPHA,BETA-UNSATURATED CARBOXYLATE ANIONS

The photochemistry of strongly alkaline solutions of cinnamate and cyclohexene-1-carboxylate anions in alcoholic solvents have been studied at two wavelengths, 2537 and >2800 Å. Unsubstituted and methyl-substituted cinnamates showed wavelength sensitivity and underwent predominant hydrogen abstraction from solvent with >2800 Å and β-lactone formation with 2537-Å light. The phenyl-substituted cinnamates showed no wavelength sensitivity. The α-phenyl derivative gave exclusively β-lactone formation and the β-phenyl derivative gave exclusive hydrogen abstraction. A low yield of product derived by hydrogen abstraction was also obtained from cyclohexene-1-carboxylate. The products of these reactions are described and possible intermediates and excited state precursors are discussed. © 1969, American Chemical Society. All rights reserved.